A lichen is any group of living organisms that consist of a fungus and algae growing together in a single unit. They are very good bioindicators of air quality. Using lichens the level of air pollution in an area can be found. The lichens will be collected off of the trees to compare the air pollution in trafficked areas to forested areas. It is expected that the species of Lichen found in a forested area will indicate that there is less pollution compared to the trafficked area.